Plants And High Temperature Flashcards
What happens to the rates of respiration and photosynthesis with an increase in temperature ?
What does this result in ?
As the temperature increases the rate of respiration increases however the rate of photosynthesis will decrease.
Respiration occurs quicker than photosynthesis causing a decrease in plant mass and eventually death.
What temperature do unadapted plants have problems coping after ?
30 degrees
Name three of the main problems caused by increased temperature in plants.
- Leaf temperatures rise 5 degrees above air temperature.
- Membranes become unstable
- Hydrogen bonds decrease in strength in proteins.
Explain evaporative cooling in tropical plants.
Leaves must have a very large surface area to volume ratio. A thin layer of water is spread across the leaves and evaporates, releasing heat with it. The leaves are dark green meaning that they have a low albedo.
Why isn’t evaporative cooling an option in savannah plants ?
As there is a low amount of water.
How is heat lost in savannah plants ?
Through conduction and convection. They have very finely divided leaves and reduce heat loss by insolation due to their high albedo. Savannah plants have phenological systems in place to increase reflection throughout the day.
Even though they have a high SA:V how do savannah plants lose heat ?
They have a very small number of stomata and have high waxiness. The high surface area but Finley divided leaves means that more heat is able to be lost via conduction due to wind.
Can savannah plants lose heat in low wind, if so how ?
Yea they can as even I low wind there is the presence of eddy currents which take heat away using convection.
What is a boundary layer and how does it effect heat loss ?
In a large flat lead the air speed of wind decreases at the surface of the leaf causing the layer of still air. This causes a decrease in heat loss by conduction.
